i have heard raves about the bower, even on B&Hs website there are 10 lovely reviews on it! that one is priced at $70 and many reviews compare it to be nearly up to par as the Sb-600!

the sb-400 also has great reviews, and i am willing to spend the $110 for it, however, the only thing that is drawing me away from it is its inability to rotate (330 degrees or 270 for example, meaning i cannot bounce it off the ceiling when i am taking vertical portrait shots)

suggestions on what would be my better option....also, what is the difference between TTL and i-TTL?!

Aside from not being able to rotate the flash is also weak very quickly running out of juice when bouncing off ceilings. I knew 2 people with SB-400s, and they were very quick to get rid of them and upgrade to SB-600s for exactly this reason. That and the SB-600 is compatible with wireless CLS so if you upgrade your camera body or get a SU-800 transmitter the SB-600 can be used wirelessly and starts looking more like an investment for the future rather than a huge expense.

The SB-400 on the other hand is nothing more than a slight boost in flash range and I doubt will be very satisfying.

No idea on the Bower.

i-TTL is just Nikon's equivalent of TTL. More information is transmitted between the flash and the camera for iTTL including CLS information on the more expensive flashes. As far as I know TTL flashes still work fine on the camera but the camera reverts to more basic metering modes such as center weighted rather than 3D Matrix Metering. Consult your manual to double check this. There will be a compatibility table in there somewhere.